Nitrocellulose lacquer



Patented May 3, 1932 entree sra'rss PATENT OFFICE GORDON H. MUTERSBAUGH, OF ROCKY RIVER,'MILTON ZUCKER AND HENRY D. HEISER, OF LAKEWOOD, AN D W ILIB'UR A. SI-IOPE, OF CLEVELAND, OHIO, ASSIGNORS TO THE GLIDDEN COMPANY, OF CLEVELAND, OHIO, AnCORPOZR'ATION OF OHIO NITROCELLULOSE LACQUER No Drawing.

This invention relates to improvement in nitrocellulose lacquers, and more particularly to that type of lacquer known to the trade as fiat lacquer, used particularly in the furniture finishing industry. 1

The history of flat lacquer is unique. Formerly all furniture was finished With varnishthe wood was stained, filled, shellacked and varnished, the varnish being rubbed with pumice stone and oil to give the dull finish desired by all first class furniture manufacturers. This was a slow and laborious process, as coatings were dried from eight to twenty-four hours before recoating, and it was necessary to dry the last coat at least twenty-fourto forty-eight hours before rubbing. The first improvement came in the socalled flat varnish. This was made by adding a transparent pigment (asbestine, clay, magnesia, insoluble metallic stearates and palmitates) to the varnish. This gave the dull sheen without rubbing.

When nitrocellulose lacquers invaded the finishing field, the use of fiatting agents in clear varnish was extended to lacquer. It was found that the agents that fiatted varnish flatted lacquer; and everybody was satisfied temporarily.

It was soon found, however, that the fiatting agents in use were not satisfactory. All inorganic pigments were of necessity present in such small quantity as to present a very serious settling and caking problem. Furthermore, they were not as transparent in lacquer as in varnish, and left a gray film. This practically eliminated them from consideration, leaving only themetallic soaps. The metallic soaps had the advantage of clarity and good flat-ting with ony a small percentage of soap, furthermore, they stayed in suspension-a property to be desired. Metallic soaps are still used by a. majority of lacquer manufacturers: but there is a very serious drawback to their use by a manufacturer who desires to supply a durable finish.

The action of sunlight has a peculiar effect on most soaps. It renders them susceptible to the action of water. lVhen a soap flat lacquer is first mad-e, the soap acts as a waterproofer in the film. After it has been exposed Application filed January 8, 1931. Serial'No. 507,430.

to ultra-violet light, however, the soap breaks 'down, and actually absorbs water into the film. The result is,-t-l1at in severe cases,the

furniture turns white due to this absorption of moisture, and the reputable lacquer manufreely employed, with the idea of producing a SOaIYiI-illt would be waterproof even after action of the sunlight. Uniformly all results were failures from the start; the films obtained with tungateshad a'blue haze which could not be overcome.

This beingout of the question, most manufacturerswent back to the stearate and palmitate flats, the condition not being serious frointheir point of View, as they refused to be responsible for thefinish after two or three years (and practically no failures occurred before such a time). The others went on to experimentwith waxy gums such as East India batu, etc., and severalproduced such a fiat lacquer. Thiswasairexcellent flat lacquer and is still iuusebut does not give uniform finishing results, even with the same drum ofllacquer because the fiatting varies with the temperature, drying conditions, etc.

The next type of flat lacquer was the wax flat. In this type of lacquer an insoluble wax was used to produce the flatting properties. The wax flatlis averyclear, hard lacquer, but it also has a very objectionable feature. The'waxloreaks upthe continuity of the film, and .ashort flat lacquer is obtained. Over shellac, this is actually'brittle. This objection, together with lack of uniformity of raw material, difficulty of grinding, and other manufacturing difliculties, led us to re-investigate the waterproof soap type of fiat lacquer.

'The bluehaze referred to abovepersisted until we prepared our own tungates, according to the method outlined in the co-pending applications of Henry D. Heiser and Milton Zucker #507,520. The haze was due to free wood oil, in our estimation, and we attribute failure of all former workers with this product to this impurity. 1

On further investigation we have found that serious manufacturing difficulties may be encountered with the use of this metallic .tungate,unless the soluble saltsof zinc or duced with other soaps; it has no haze due to free oil; it will resist the action of ultra violet light, and has the normal life of an a clear nitrocellulose lacquer and a neutral metallic tun-gate.

2. A fiat nitrocellulose lacquer composed of a clear nitrocellulose lacquer and a neutral zinc tungate.

GORDON H. MUTERSBAUGH. MILTON ZUCKER. HENRY D. HEISER. "WILBUR A. SHOPE.

inside protective coating of considerably more than two or three years;

Preferably zi c tungate. described in the co-pending application of Henry D. Heiser and Milton Zucker (above mentioned) in a finely divided state. is added to a solution of nitrocellulose. We do not, however, limit ourselves to the use of such a paste, it being I merely the most desirable method of adding the zinc tung'ate. The neutral zinc tungate may also be precipitated, washed, and

very. carefully dried by heat (extreme care must be taken to avoid decomposition) and then ground in a stone, roller. or pebble mill With castor oil, ester gum solution, dibutyl phthalate or nitrocellulose solution, as the formulator desires. not as good as the first, if extreme care is taken there will be little or no haze.

The unsrate may be used alone, or with other flatting agents. It may be used to flatten any clear nitrocellulose lacquer, where it is desiredto obtain the rubbed effect without rubbing. Furthermore, it has another distinct advantage. Some-finishing shops want diiferent'sheens on different parts of the furniture; they use one lacquer, and rub to the desired sheen. Tungate'flats stand this rubbins: very nicely. V M V The clear lacquers maybe'nitrocellulose solutions in any lacquer solvents, with or without the addition of plasticizers such as castor oil, rapeseed oil, dibutyl phthalate, etc., or gums such as ester, damar, elemi, synthetic amberols and glyptals, etc, infact,

any'clear lacquermay be fiatted with metallic tungate. soap, but aluminum, calcium and magnesium tungates may also be used.

Having thus described ourinVent-ion, what" we claim is 1.. A flat nitrocellulose lacquer composedpf While this method is Z1118 tungate isperhaps'the best 

